| 1. |
- Strogyloudi, Evangeli, et al.
(författare)
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Estimating the accumulation and transfer of Nodularia spumigena toxins by the blue mussel Mytilus edulis: An appraisal from culture and mesocosm experiments
- 2006
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101 .- 1879-3150. ; 48:4, s. 359-372
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Tidskriftsartikel (refereegranskat)abstract
- Accumulation of Nodularia spumigena toxins by Mytilus edulis was studied during laboratory and mesocosm experiments in order to investigate the possible pathways of nodularin in mussels and calculate toxin budgets. Mussels were exposed to 0.2-15.6 mu g nodularin 1(-1), fed for up to 5 days with Nodularia cells from culture, or blooming in different nutrient-treated seawater. Toxin concentration was monitored with LC-ESI-MS.During different exposures, the amount of nodularin detected in mussels increased linearly with increasing toxin concentration in food and attained 0.28-13.8 mu g of nodularin g dw(-1) of the mussel whole body tissue after 12h. The digestive gland was found to be the tissue with the highest toxin concentration. Nodularin concentration in faeces was not proportional to faeces production or to toxin concentration in food; however, it seemed to be mostly related to food quality as well as to food availability. The percentage of nodularin taken up by the mussels, relative to the amount contained in the offered food, varied from 10% to 20%, depending on food quality. During a 5-day toxin accumulation experiment, the acute reduction of the toxin in mussel tissues the second day and the following stabilization, showed that probably mussels maintain low toxin levels via efficient elimination and/or toxin metabolism. After a 72 h depuration period, mussels showed 75% reduction in their toxin content.
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| 2. |
- Hansson, Karin M, et al.
(författare)
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Cysteine-rich secretory proteins in snake venoms form high affinity complexes with human and porcine beta-microseminoproteins.
- 2009
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101. ; 54, s. 128-137
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Tidskriftsartikel (refereegranskat)abstract
- beta-Microseminoprotein (MSP), a 10kDa protein in human seminal plasma, binds human cysteine-rich secretory protein-3 (CRISP-3) with high affinity. CRISP-3 is a member of the family of CRISPs, which are widespread among animals. In this work we show that human as well as porcine MSP binds catrin, latisemin, pseudecin, and triflin, which are CRISPs present in the venoms of the snakes Crotalus atrox, Laticauda semifasciata, Pseudechis porphyriacus, and Trimeresurus flavoviridis, respectively. The CRISPs were purified from the venoms by affinity chromatography on a human MSP column and their identities were settled by gel electrophoresis and mass spectrometry. Their interactions with human and porcine MSPs were studied with size exclusion chromatography and surface plasmon resonance measurements. The binding affinities at 25 degrees C were between 10(-10)M and 10(-7)M for most of the interactions, with higher affinities for the interactions with porcine MSP compared to human MSP and with Elapidae CRISPs compared to Viperidae CRISPs. The high affinities of the bindings in spite of the differences in amino acid sequence between the MSPs as well as between the CRISPs indicate that the binding is tolerant to amino acid sequence variation and raise the question how universal this cross-species reaction between MSPs and CRISPs is.
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| 3. |
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| 4. |
- Mussagy, Aidate, et al.
(författare)
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An experimental study of toxin production in Arthrospira fusiformis (Cyanophyceae) isolated from African waters
- 2006
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101. ; 48:8, s. 1027-1034
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Tidskriftsartikel (refereegranskat)abstract
- Arthrospira is one genus of cyanoprokaryota for which information on toxin production exists for only a few strains. The purpose of this study was to investigate whether strains of Arthrospira fusiformis produce intracellular toxic compounds such as microcystins and anatoxin-a. The study was based on three strains of Arthrospira, two strains isolated from wastewater ponds in Mozambique and one from Lake Nakuru, Kenya. These strains were cultivated experimentally in different light intensities and salinities. Microcystins were analysed by ELISA and HPLC and anatoxin-a by HPLC. Toxicity analysis of the three strains, following the growth cycle, detected neither microcystins nor anatoxin-a. The results indicated that the strains selected were not toxigenic under the experimental conditions applied. Thus, the strains of A. fusiformis tested in the present study could be considered candidates for use in different applications such as in food supplements and in aquaculture.
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| 5. |
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| 6. |
- Teneva, I, et al.
(författare)
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Toxic potential of five freshwater Phormidium species (Cyanoprokaryota)
- 2005
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101. ; 45:6, s. 711-725
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Tidskriftsartikel (refereegranskat)abstract
- Among the Cyanoprokaryota (blue-green algae), the genus Phormidium has thus far rarely been studied with respect to toxin production and potentially resulting human and environmental health effects. We here show that five previously unexplored freshwater species of this genus (Ph. bijugatum, Ph. molle, Ph. papyraceum, Ph. uncinatum, Ph. autumnale) are indeed capable of producing bioactive compounds. Phormidium extracts caused weight loss as well as neuro/hepatotoxic symptoms in mice, and in the case of Ph. bijugatum even death. Very low levels of saxitoxins and microcystins, as confirmed by ELISA, were insufficient to explain this toxicity and the differing toxic potencies of the Phormidium species. Qualitative HPLC analyses confirmed different substance patterns and in the future could aid in the separation of fractions for more detailed substance characterisation. The results in vivo were confirmed in vitro using cells of human, mouse and fish. The fish cells responded least sensitive but proved useful in studying the temperature dependence of the toxicity by the Phormidium samples. Further, the human cells were more sensitive than the mouse cells thus suggesting that the former may be a more appropriate choice for studying the impact of Phormidium to man. Among the human cells, two cancer cell lines were more responsive to one of the samples than a normal cell line, thereby indicating a potential anti-tumour activity. Thus, the five freshwater Phormidium species should be considered in environmental risk assessment but as well, as a source of therapeutic agents.
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| 7. |
- Torgersen, T., et al.
(författare)
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Profiles and levels of fatty acid esters of okadaic acid group toxins and pectenotoxins during toxin depuration, Part I: Brown crab (Cancer pagurus)
- 2008
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101. ; 52:3, s. 407-417
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Tidskriftsartikel (refereegranskat)abstract
- In 2002, two outbreaks of diarrhetic shellfish poisoning (DSP) occurred in Norway, which was later confirmed to be caused by the consumption of brown crab (Cancer pagurus) contaminated predominantly by esters of okadaic acid (OA) after feeding on toxic blue mussels (Mytilus edulis). In addition to OA-group toxins, pectenotoxins (PTXs) are commonly detected in the toxin-producing algae (i.e. Dinophysis). In this paper, an experiment was set up to study the fatty acid ester profiles and depuration rates of OA-group toxins and PTXs from C. pagurus after feeding on M. edulis containing these toxin groups. CA, DTX1, DTX2 and PTX2 SA were all detected primarily in the form of fatty acid esters in the crab hepatopancreas (HP). Crabs preferentially assimilated toxins of the OA group after feeding on the mussels for 1 week. Detailed analysis of the fatty acid ester profile in crabs and mussels showed that the ester profiles in the crabs differed slightly from profiles of the fatty acid esters in M. edulis, but neither ester profile nor ester to free toxin ratio appeared to change in the crabs during the first 2 weeks of deputation. Calculations of deputation rates of the free forms of toxins resulted in similar reduction rates for OA and DTX2, whereas the depuration rate of DTX1, PTX2 and PTX2 SA was considerably faster. From the industrial perspective, the PTX-compounds are of minor importance compared to the OA group toxins in crabs, considering (1) the uncertainty regarding the oral toxicity of the PTXs, (2) the preferential ingestion of OA-group toxins compared to PTXs and (3) the faster depuration of PTXs. (C) 2008 Elsevier Ltd. All rights reserved.
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| 8. |
- Torgersen, T., et al.
(författare)
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Profiles and levels of fatty acid esters of okadaic acid group toxins and pectenotoxins during toxin depuration. Part II: Blue mussels (Mytilus edulis) and flat oyster (Ostrea edulis)
- 2008
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Ingår i: Toxicon. - : Elsevier BV. - 0041-0101. ; 52:3, s. 418-427
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Tidskriftsartikel (refereegranskat)abstract
- Bivalve molluscs accumulate toxins of the okadaic acid (OA) and pectenotoxin (PTX) groups, which are frequently found in Dinophysis spp. Transformation of the OA-group toxins into fatty acid ester derivatives (often designated "DTX3") is common in many bivalve species but the degree to which these toxins are transformed vary between species, and is also depending on the parent toxin involved. In this paper, detailed profiles and levels of fatty acid esters of OA, DTX1, DTX2 and PTX2 SA were studied in blue mussels (Mytilus edulis) and European flat oysters (Ostrea edulis), collected during a bloom of Dinophysis spp. and after 3 and 6 weeks of depuration. Analysis of samples by HPLC-MS/MS and HPLC-MS2 revealed some differences in identity and abundance of fatty acid moieties of the OA-group esters between species, but the 16:0 fatty acid esters dominated in both oysters and mussels, which is in accordance with the free fatty acid profiles in these species. A wider range of FM SA-esters were detected compared to esters of the CA-group toxins in both mussels and oysters, and in oysters, both 14:0, 18:4 and 20:5 fatty acid side chains were more common than 16:0. OA-group toxins were esterified to a larger degree in oysters (83-93%) compared to mussels (21-41%), and in mussels a higher proportion of OA was esterified compared to DTX1 and DTX2. Contrary to what was observed for CA-group toxins, PTX2 SA was esterified to a larger degree in mussels (81%) compared to oysters (64%). Calculations of depuration rates for all individual esters of each parent compound showed that the esters of DTX1 depurated significantly slower from both mussels and oysters compared to esters of OA, DTX2 and PTX2 SA, but overall the deputation rates of esters of both toxin group were highly similar for both species. This indicated that differences in depuration rates are not causing the large species-specific differences in levels and profiles of these toxins. Instead, the results for the CA-group toxins suggested that a higher rate of esterification in oysters is the main factor causing the observed differences in the proportion of esters to free toxin. For FM SA, large differences in ester profiles and a higher proportion of esters of PTX2 SA in mussels compared to oysters suggested differential assimilation and metabolic rate processes for the PTXs compared to OA-group toxins between these species. Hence, although produced by the same Dinophysis species, conclusions about the dynamics of one toxin group based on results from the other group should be avoided in future studies. (C) 2008 Elsevier Ltd. All rights reserved.
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| 9. |
- Wising, Catharina, 1973, et al.
(författare)
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Induction of apoptosis/necrosis in various human cell lineages by Haemophilus ducreyi cytolethal distending toxin.
- 2005
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Ingår i: Toxicon : official journal of the International Society on Toxinology. - : Elsevier BV. - 0041-0101. ; 45:6, s. 767-76
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the impact of highly purified Haemophilus ducreyi cytolethal distending toxin (HdCDT) on the apoptosis and necrosis of various human cells; including myeloid cells, epithelial cells, keratinocytes, and primary fibroblasts. The levels of apoptosis and necrosis induced in these cells were compared to those induced by HdCDT in human T cells and in the Jurkat T cell line. Levels of caspase-3 activity were measured, and membrane changes like phosphatidylserine (PS) translocation was evaluated after double-staining with the fluorescein isothiocyanate (FITC)-labeled annexin V and propidium iodide (PI) using flow cytometry. HdCDT induced various degrees of apoptosis and necrosis in dose- and time-dependent manners in cells of various lineages. Early and late apoptosis (annexin V-stained cells) were induced in more than 90% of T cells and monocytes after treatment with 100 ng/ml HdCDT for 24 and 48 h, respectively. The corresponding numbers for epithelial cells, keratinocytes, and fibroblasts were 26-32% after treatment with 100 ng/ml HdCDT for 48 h. HdCDT appears to eliminate effectively by inducing apoptosis those cells that are involved in immune responses. Epithelial cells, keratinocytes and fibroblasts, which are important for the healing of chancroid ulcers, are eliminated by apoptosis or necrosis after contact with HdCDT, albeit slower and to a lesser extent than T cells.
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